If you have Photoshop, I suggest the following steps. It is a really classy border that I use a lot.
1. Open the picture
2. CTRL + A to select the picture, CTRL + C to copy, CTRL + V to paste (basically creating a duplicate layer of the photo)
3. Image > Canvas Size, change Inches to Pixels
4. Increase both dimensions by a good amount. If the picture is 800×600, increase each dimension by 80 pixels. If it is 2000×3000, increase each by 200 or so.
5. CTRL + Click the top layer in the layers pallette
6. CTRL + SHIFT + I to invert the selection
7. Click on the background layer in the layers palette.
8. CTRL + V
9. Move the new layer to the top on the layers palette.
10. Open the layer styles for this layer.
11. Color Overlay > Black, 100%
12. Stroke: Change 3 to 2 for the width. Change color to gradient. Change Linear to Shape Burst.
13. Click on the gradient.
14. Move the position sliders on the bottom so that they are both at 50%. It’s easiest to just type fifty into the position field.
15. Click OK
16. Click OK on the layer styles window.
17. CTRL + SHIFT + E
Done!
